docs: def _is_robot():
      """
      Return `True` if the current visitor is a robot or spider, or
      `False` otherwise.
  
      This function works by comparing the request's user agent with a regular
      expression.  The regular expression can be configured with the
      ``SPLIT_ROBOT_REGEX`` setting.
      """
      robot_regex = current_app.config['SPLIT_ROBOT_REGEX']
      user_agent = request.headers.get('User-Agent', '')
      return re.search(robot_regex, user_agent, flags=re.VERBOSE)